String tension adjustment device for stringed instrument



April 196% P. J. NORWOOD 3,440,920

EVICE FOR STRINGED INSTRUMENT STRING TENSION ADJUSTMENT Sheet of3 Filed Nov. 1, 1966 PAUL J. NORWOOD ATTORNEY 5 STRING TENSION ADJUSTMENT DEVICE FOR STRINGED INSTRUMENT sheetiofs Filed Nov. 1, 1966 m U m m@ mm mm m m R vw K N wn 1 m @m J. M w H MUM [I P J L m w n M m U M @W w ww M. N u" .0 I l mm mm mm Q h J R Q 9. o E 8. E. 82 T 3. MN Q... f? w vm v a wwfiw mm mm Q w ON 3 &0 Q 9% 0 April 1969 P. J. NORWOOD 3,440,920

STRING TENSION ADJUSTMENT DEVICE FOR STRINGED INSTRUMENT Filed Nov. 1, 1966 Sheet 44 34 2O 43 2 .mamam:

I 48 46 l 3 5O {2O 34 4 3e 44 r ig 5| PAUL J. NORWOOD BY f) N. -2 0/ 7/ p ZULU V 2 2/ LL ATTORNEYS United States Patent ABSTRACT OF THE DISCLOSURE There is disclosed a stringed musical instrument having a plurality of adjustably tensioned longitudinally disposed strings supported at end portions thereof, means for selectively altering the tension of predetermined ones of the strings relative to a pre-set degree of adjusted spring tension for sharping or flatting said predetermined strings, said means including first pivotal members providing individual supports for the springs at one end thereof and longitudinally reciprocable members directly connected with the first pivotal members so that when moved in one direction they will move the first pivotal members in a string flattening direction and when moved in the opposite direction will move the first pivotal members in a string sharping direction, and manually controllable means for actuating the longitudinally reciprocable members.

This invention relates in general to stringed instruments, and more particularly to steel guitars having means therein for flatting or sharping notes or chords, as desired.

Steel guitars of the prior art types have been provided with foot pedals which are adapted, When actuated, to increase or decrease the tension in one or more guitar strings by a predetermined amount, in order to either sharpen or flatten a note or chord, as desired. In this way, as many different notes or chords as there are foot pedals, or combinations thereof, may be programmed into the guitar, thereby taking some of the burden of playing off of the musicians hands. A guitar ma thus be pre-set with several commonly used or diflicultly obtained notes or chords.

Prior art devices have failed to provide a means whereby a single string could be sharpened on one pedal and flatted on another pedal, or vice versa; Also, prior art devices have failed to provide an eflicient pedal operated mechanism for flatting a desired string with the same degree of facility with which one may sharp a string. Even further, prior art devices have failed to provide readily adjustable mechanisms, whereby the notes or chords which are to be pre-set into the instrument may readily be varied or changed, as desired.

The present invention seeks to overcome the ditficulties inherent in guitars of the prior art types by providing a pedal-operated means associated with a steel guitar, for allowing the musician to pre-set into the instrument such additional sharps, flats, or chords, as desired, and wherein strings may be flattened with the same facility with which they are sharped, and wherein adjustability and changeability of the notes or chords is readily obtained.

Accordingly, it is a primary object of this invention to provide a novel stringed instrument, having pedal operated means thereon for facilitating the sharping or flatting of one or more strings, or to enable a musician to readily play additional chords, all of which may be pre-set into the instrument and which operate through a novel linkage means to alter the tension in the strings of the instrument.

It is another object of this invention to provide a novel stringed musical instrument having a plurality of strings, and means for selectively altering the tension of predetermined ones of the strings relative to a pre-set string tension, through the operation of mechanisms comprising pivot members, longitudinally movable members, and actuating members of the pedal type.

It is a further object of this invention to provide, as a component of a stringed musical instrument, a pedaloperated pivotally movable lever means, having upper and lower adjustment means thereon associated with each instrument string, for pre-setting into the instrument a desired increase or decrease in string tension upon actuation of an associated pedal.

It is another object of this invention to provide a novel string tension adjustment mechanism for a musical instrument, including longitudinally movable bar members, each associated with a respective string, and a plurality of bar actuatin levers, each adapted for engagement with any or all of the longitudinal bar members, as desired, and pedal-operated means adapted for engagement and actuation of the lever means.

It is a further object of this invention to provide a stringed musical instrument including a sound board having the center portion thereof removed, a tuning head assembly and string tension adjusting assembly at opposite ends of the board with strings disposed therebetween, a removable cover for the board and a pedal operated means for altering the tension of selected ones of the strings to pre-set degrees.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:

FIGURE 1 is a top perspective view of the steel guitar embodying the string-tension adjusting mechanisms of this invention, and wherein all of the components of the guitar are illustrated in their respective operating positions.

FIGURE 2 is an enlarged perspective view, partially exploded, of portions of the operating mechanisms of this invention, the view being taken along the lines 2-2 of FIGURE 1.

FIGURE 3 is an enlarged longitudinal sectional view of the operating mechanisms for all of the strings of this invention, also taken along the line 22 of FIGURE 1.

FIGURE 4 is an enlarged fragmentary 'bottom plan view of some of the operating mechanisms for adjusting the string tension in the guitar of this invention, taken along the line 44 of FIGURE 3, and wherein there is illustrated the mechanical association of the pivotally movable levers and longitudinally movable bars of the string tension adjusting mechanisms of this invention.

FIGURE 5 is an enlarged fragmentary cross-sectional view of the guitar of this invention, taken along the line 5-5 of FIGURE 3.

FIGURE 6 is an enlarged fragmentary bottom view of the spring stop mechanism for the longitudinally movable rod of this invention, taken along the line 6'6 of FIGURE 3.

'FIGURE 7 is an enlarged fragmentary longitudinal sectional view taken along the line 7-7 of FIGURE 6, and wherein there is illustrated the interconnection of a longitudinally movable rod, a rocker arm, the springbiased rocker arm stop, and a guitar string.

FIGURE 8 is an enlarged fragmentary longitudinal sectional view of a pivotally mounted flatter-sharper lever and an associated longitudinally movable bar of this invention, and wherein there is illustrated the actuation of the longitudinally movable bar in a rightward or string tensioning condition by the pivotal movement of lever with an adjustment means between the lever and bar mean-s.

FIGURE 9 is a view similar to that of FIGURE 8, but wherein the adjustment means is located on a lower portion of the lever, and is adapted for movement of the longitudinally movable bar to the left, towards a string relaxing or flattening condition.

Referring to the drawings in detail, reference is first made to FIGURE 1, wherein there is illustrated a guitar generally designated by the numeral 12, comprising a board 13, a tuning portion 14, a head portion 16, pedal mechanisms 17 and tensioning mechanisms 18.

The board 13 has a generally rectangular cut-out 20 extending therethrough, with one end thereof having -cut away portions 21 on opposite sides of the cut-out 20. The board 13 is supported by four adjustable legs 22, two of which have a horizontal member 23 disposed therebetween for support, and to provide a pivot base for the pedal mechanism 17. The board 13 may be of any de sired material, but Curly Maple and Birds Eye Maple have been found to be desirable.

The tuning mechanism 14 comprises a base 24 having upstanding lugs 25 and 26 which facilitate the retention of a shaft 27 therebetween. A number of rollers 28 are mounted on the shaft 27, corresponding to the number of guitar strings. The guitar illustrated in FIGURE 1 utilizes six strings, thus there are six rollers 28 disposed on the shaft 27. Conventional worm gear adjusting means 30 are provided, carried by the base 24 of the tuning mechanism 14.

The head portion 16 includes a base 31 having upstanding bosses 32, 33 retaining a shaft 34 therebetween. The base 31 is secured beneath the board 13 with the bosses 32 and 33 extending upwardly through the cut-out portion 20 of the board 13, and with the bosses 32 and '33 secured within the undercut portions 21 of the board '13.

The base 31 includes first and second cross members 34 and 35, with respective small and larger diameter aligned bores 36 and 37, each set of aligned bores being disposed in alignment with an associated guitar string 38. A set of stop members 40 are disposed within the base 31 of the head portion 16, each of which includes a small diameter rod 41, a large diameter portion 42, a head 43, and an associated washer 44. The length of the enlarged diameter portion 42 of each member 40, is greater than the thickness of the second cross member to facilitate a predetermined amount of longitudinal movement of the enlarged diameter portion '42 within the bore 37. The small diameter portion 4 1 of each of the members is carried within the associated bore 36, for sliding engagement therethrough, with a compression spring 45 mounted between the washer '44 and -first class member 34.

A number of rocker arms 46, corresponding to the number of guitar strings 38, are provided mounted on the shaft 34, for pivotal engagement thereabout. Each rocker arm 46 includes an upper arcuate portion 47, terminating in a claw portion 48. A lever arm 50 extends vertically downwardly from the arcuate portion 47 of each rocker arm 46, terminating in a forked end 51. 'Each guitar string 38 is mounted at one end to the adjusting or tuning mechanism 30, is carried over associated roller 28, and is cross-pin mounted at its other end within the claw '48 of an associated rocker arm 46.

A horizontally movable member 52 is provided and associated with each guitar string 38, comprising extension rod portion 53 and activator bar portion 54, secured together, as in threaded engagement. The left end of the extension rod portion 53, as viewed in FIGURE 2, includes a flattened portion 55, carried within the channel or void of the forked end 51 of an associated rocker arm '46, and mounted therein for pivotal engagement about pivot shaft 56.

A retractile spring 57, adjustment means 58, and connecting rod 60, are provided for each rocker arm '46, the connecting rod 60 being secured to the flattened portion 55 of an associated extension arm 53 at one end, the connecting rod being secured to the spring 57 at an opposite end. The adjustment means '58 is secured to the remaining end of the extension spring '57 with the adjustment means 58 being carried by an adjustment support 61 secured beneath the board 13 at opposite sides of the cut-out 20, which board also carries members 68, 70, disposed depend below the cutout portion 20 thereof, and to be later described. See FIGURES 3 and 15.

The activator bar portions 54 of the members 52, associated with guitar strings 38, are slidably carried by guide rods 62, 63, 64 and 65, mounted on the depending members 68, 70 and disposed across the cut-out portion 20 of the board 13, for slidable engagement of the activator rods 54 between cooperating pairs of rods 62, 63 and 64, 65. Each of the activator bars 54 is of generally rectangular cross section, to prevent rotation of the activator bars 54 when they are engaged between the guide rods 62 through 65 as shown in FIGURES 3 and 4. Each of the activator rods 54 includes five upwardly extending lug members 66 and five downwardly extending lug members 67, arranged in pairs as shown in FIGURES 2, 3, 8 and 9.

As before stated, a pair of bearing support members 68, are secured to the underneath of the board 13, adjacent opposite sides of the cut-out portion 20 thereof, by means of screw-type fasteners 71. Each of the bearing support members 68 and 70 has five transverse horizontally disposed equidistantly spaced bores 72 therein and four smaller bores 73, 74, 75 and 76. The latter bores 73 through 76 are adapted to receive therein respective transfer rods 62 through 65. See FIGURE 5.

Five flatter-sharper levers 77 each in the form of an open rectangular frame, are provided, each comprising an upper and a lower horizontal bar 78 and 80 respectively, with connecting end bar members 81 and 82 therebetween. Shaft members or trunnions 83 and 84 are provided, extending outwardly of respective connection bars 81 and 82. Each shaft or trunnion member 83 has a flattened portion 85 thereon to facilitate pivotal driving of the flatter-sharper lever 77, as shown in FIGURE 2. Each of the upper and lower horizontal bars 78 and 80 of the flatter-sharper lever 77 has six tapped holes 86, lextending therethrough, corresponding to the number of guitar strings 38, the tapped holes 86 being adapted to receive therein adjustable flat head abutment members in the form of adjustably mounted screw members 87.

The shaft members 83 and 84 of each flatter-sharper lever 77 are pivotally received within the bores 72 of the respective bearing supports 68 and 70.

A crank link 88 is provided, having a hole 90 with a flattened side portion thereof extending therethrough at one end and adapted to engage the flattened portion 85 of an associated shaft member 83 of a flatter-sharper lever 77. An opposite end 91 of each crank link 88 has a bore therein, for receiving an inturned end 92 of a vertically disposed pedal rod 93'. A retractile spring 89 is provided, secured to the inturned end 91 of the pedal rod 93 at one end, and secured to the undersurface of the guitar board 13 at the other end, in order to insure a normal upward position for each pedal of the pedal mechanism 17. See FIGURES 2 and 5.

The pedal mechanism 17 also includes five pedals 94, corresponding to the number of flatter-sharper levers 77. Each pedal 94 includes a lever portion 95,.having a bore 96 therein for pivotally receiving a lower end of each associated pedal rod 93 therein, and a shaft engaging portion 97 for mounting about a pivot shaft 98. The pivot shaft 98 is secured by bosses 100 and 101, at opposite ends thereof, to the cross member 23 extending between guitar legs 22.

In the operation of the guitar 12 of this invention, the strings 38 will be tuned in the usual manner and to the predetermined degree by the tuning device 14. As the strings 38 are tuned, the forked ends 51 of the rocker arm 46 will be in positions abutting the heads 43 of associated rod members 40, with the springs 45- free and uncompressed. At this time, the adjustment means 58 associated with the retractile springs 57 may be so adjusted to ease the pull of each string 38, in counter-balancing the tension or pull in the strings 38. Thus far, the guitar 12 may be played as an ordinary guitar, lacking the refinements set forth in the present invention.

If it is desired to pre-set certain normally used chords into the guitar 12, or to pre-set certain strings 38 to conditions of sharping or flatting, such that, upon actuation of one of the pedals 94, the desired sharping or flatting of one or more of the strings will be effected to enable the guitar to play one or more desired predetermined notes or chords, the screw-type adjustable abutment means 87 may be placed within selected tapped holes 86 on the flatter-sharper levers 77 corresponding to the selected string or strings with which the selected tapped hole or holes 86 are cooperatively related.

Once the desired chord arrangement has been set, the musician way, by pressing upon a pedal 94, thereby drawing the pedal rod 93 downwardly against the force of the spring 89, and turning the crank link 88 to which the pedal rod 92 is attached through the pivot bore 91 therein, pivot the crank link 88. By pivoting the link 88, an associated attached flatter-sharper lever 77 is also pivoted, the link 88 driving against the flattened surface 85 of the shaft portion 83, and the shaft portions 83 and 84 pivoting within the bearing portions 72 of the supports 68 and 70. Referring to FIGURE 3, each flattersharper lever or frame 77, when thus actuated by pressing on a foot pedal 94, will always be pivoted in a clockwise direction.

Should an abutment screw 87 be provided within a tapped hole 86 in an upper horizontal bar 78, the tapped hole 86 being aligned with an upstanding lug 66 of a longitudinal member 54, the pivoting of a flatter-sharper lever 77 will cause the adjustment screw 87 to engage an adjacent surface of the upstanding lug 66 as shown in FIG- URE 8, whereby continued pivoting of the flatter-sharper lever 77 will cause the longitudinal member 54 to move to the right, as viewed in said FIGURE 8. Movement of a member 54 to the right, causes movement of a rod member 53 to the right, and pivoting of the flattened portion 55 of the rod member 53 about the pivot shaft 56, followed by pivoting of the associated rocker arm 46 in a counterclockwise direction about the pivot shaft 34, whereby the associated guitar string 38 is subjected to an increase in tension which will provide a consequent sharping of the string 38. The degree of increase in tension, or sharpening may be pre-set by the adjustment of the screw means 87 within the tapped hole 86 on the upper bar 78 of the flatter-sharper lever 77.

Upon removal of the foot of a musician from the pedal 94, the spring 89 is operable to return the pedal to its normal upward position, also returning the crank link 88 to its normal upward position, thereby pivoting the flattersharper lever 77 in a counter-clockwise direction, whereby the screw 87 within a tapped hole 86 on the upper bar 78 of the flatter-sharper lever 77 is moved out of engagement with the upwardly extending lug 66 of the longitudinal bar member 54, whereby no additional tension is being applied to the guitar string 38, the string 38 being thus free to return to its original length, pivoting the rocker arm 46 in a clockwise direction until the forked end portion 51 of the rocker arm 46 again abuts against the head portion 43 of the rod member 40, also drawing the rod member 53 and attached bar member 54 to their original leftward position as viewed in FIGURE 3.

If it is desired to flat a particular string, upon actuation of a pedal 94, a screw-type abutment means 87 will be screwed into an associated tapped hole 86 on a lower horizontal bar 80 of the fiatter-sharper lever 77, the hole 86 being aligned with the associated string 38 which is desired to be flatted. See FIGURE 9. Upon adjustment of the screw 87 to the desired amount, and subsequent depression of the pedal 94, the pivot link 88 will be pivoted in a clockwise direction, as viewed in FIGURE 2, thereby pivoting the flatter-sharper lever in a clockwise direction as viewed in FIGURES 2 and 9, forcing the head of the screw 87 into abutment against an adjacent surface of a depending lug 67 of the longitudinal bar 54, as shown in FIGURE 9. The bar 54 will thus be driven to the left, as viewed in FIGURE 9, whereby the rod 53 connected to the forked end portion 51 of the rocker arm 46, will force the forked end 51 of the rocker arm 46 to the left, as viewed in FIGURE 3, against the force of the compression spring 45, whereby the rocker arm 46 will be pivoted in a clockwise direction, a predetermined amount suflicient to slacken or flat the connected string 38 the desired amount.

Upon removal of the foot of the musician from the pedal 94, the spring 89 is again operable to return the pedal 94 to its original upward position, as well as returning the flatter-sharper lever 77 counter-clockwise, to its original position, wherein the screw 87 is no longer in engagement with the depending lug 67 of the longitudinal bar 54. The compression spring 45 is thus free to drive the rod 40 to the right, as viewed in FIGURES 2 and 3, thereby engaging the forked end 51 of the rocker arm 46, and pivoting the rocker arm 46 in a counter-clockwise direction, thereby increasing the tension in the string 38 to its original degree, whereby the longitudinal rod 53 and longitudinal bar 54 are also forced to the right, as viewed in FIGURE 3, to their original respective positions.

It is readily apparent that, with this arrangement, a single flatter-sharper lever 77 used in conjunction with a single longitudinal bar 54, cannot be used to both flatten and sharpen a given string 38. However, a given string 38 could be pre-set, such that, when different pedals 94 were actuated, different corresponding flatter-sharper levers 77 would be pivoted, further actuating different lugs 66 and 67, in different pairs, to achieve a desired predetermined sharping and flatting of a given string, depending upon the pedal which would be actuated.

It is also readily apparent, that with this invention, a single pedal 94 and a corresponding single flatter-sharper lever 77 may be used to either flat or sharp all six strings 38 of the guitar 12, if such a chord was desired by pre-setting screws 87 in tap holes 86 in the desired upper and lower horizontal bars 78 and 80, for corresponding engagement with desired ones of the upstanding and depending lugs 66 and 67. Thus, by providing five pedals, five different chords, string sharpings, string fiatings or other string arrangements may be obtained without adjustment. Also, by striking two or more pedals concurrently, various other arrangements may be effected as desired.

Even further, if it was desired, all strings could be sharped or flatted simultaneously as desired, or various combinations of the same could be effected by merely actuating a single pedal.

A further advantage of this invention lies in the fact that, whereas normal electric guitars utilize two rollers for each string, and if any string tension adjustment is desired such is accomplished at a point remote from one of the rollers, the present invention eliminates the necessity of a string passing over two rollers, making it only necessary for the string to pass over a single roller 28, the string being tensioned as desired by pivoting of the rocker arm 46, to which it is attached. This arrangement minimizes string breakage, in requiring a minimum number of bends of each of the strings 38.

It is also apparent that this invention is not limited to a six string, five pedal guitar, but is equally adapted for guitars having any number of strings, such as twelve strings, and that additional or fewer foot pedals with their accompanying mechanisms may be utilized, as desired, in order to pre-set as many tunings into a guitar as are desired.

From the foregoing, it will be seen that novel and adavntageous provisions have been made for carrying out the desired end. However, attention is again directed to the fact that additional variations may be made in this 7 invention without departing from the spirit and scope thereof.

I claim:

1. A stringed musical instrument having a plurality of adjustably tensioned longitudinally disposed strings supported at end portions thereof, means for selectively altering the tension of predetermined ones of said strings relative to a pre-set degree of adjusted string tension for sharping or flatting said predetermined strings, said means including pivotal members providing individual supports for the strings at one end thereof and longitudinally reciprocable members directly connected with said first pivotal members so that when moved in one direction they will move said first pivotal members in a string fiatting direction and when moved in the opposite direction will move said first pivotal members in a string sharping direction, and manually controllable means for actuating said longitudinally reciprocable members.

2. The instrument of claim 1 wherein second pivotal members are provided and said longitudinally reciprocable members are disposed for engagement by and predetermined limited movement in response to pivotal movement of said second pivot members.

3. The instrument of claim 2 wherein adjustable abutment members are provided on said second pivotal members for varied position contacts with said longitudinally reciprocable members for imparting movements of reciprocation to said longitudinally reciprocable members.

4. The instrument of claim 2 wherein said longitudinally reciprocable members each comprises a bar having thereon a plurality of pairs of spaced lugs between which the second pivotal members are engageable.

5. The instrument of claim 4 wherein said second pivotal members each comprises an open rectangular frame having upper and lower bar portions for driving ocntact with said'lug pairs.

6. The instrument of claim 5 wherein the adjustable abutment members are provided at selected positions on said bar portions for engagement with selected pairs of said bar lugs.

7. The instrument of claim 3 wherein the adjustable abutment members are placeable to be effective in simultaneously imparting movement to all of the first pivotal members connected reciprocable members or to selected one thereof.

8. The instrument of claim 5 wherein the reciprocable bars pass through the open rectangular frames and said frames are disposed transversely with relation to said bars.

9. The instrument of claim 5 wherein said adjustable abutment members comprise screws mounted in tapped holes in the frame bar portions, each tapped hole being correlated in position to a particular bar lug and tensioned string.

10. The instrument of claim 5 wherein said manually controllable means comprise individual depressable pedal means and spring return means operatively connected to each said second pivotal means for imparting rocking movement to the open rectangular frames.

11. The instrument of claim 1 wherein a stop means is provided and placed for engagement with each first pivotal member when its supported string tension has been pre-set, and back-up spring means to return the stop to its initial position after each displacement by a flatting adjustment of the engaging first pivotal member.

12. The instrument of claim 11 wherein there also is provided adjustable spring means connected to each first pivotal member and operable as a string tension counterbalance.

13. The instrument of claim 1 wherein each of the strings is supported at one end on a tension adjusting means and by an adjacent associated roller and is pivotally tensioned at its other end on one of the first pivotal members.

References Cited UNITED STATES PATENTS 3,352,188 11/1967 Fender 84-312 2,257,995 10/1941 Abrams et al. 843l2 2,914,982 12./1959 La Bossier 84312 2,122,396 12/1936 Freeman 84-312 3,136,198 6/1964 Smith et a1. 84312 RICHARD B. WILKINSON, Primary Examiner.

J. F. GONZALES, Assistant Examiner. 

